针对超声自动C扫描系统检测过程中的超声A扫描信号闸门调节展开研究,提出了一种适用于变厚度工件的多闸门动态跟踪方法。其基本原理是在变厚度工件的上下表面回波之间设置检测闸门,同时跟踪上表面回波与底面回波,改善脉冲反射法检测过程中变厚度工件上表面或底面的界面变化导致的回波位置变动现象,降低干扰波影响,将闸门记录的有效数据最大化。最后,通过对含有人工缺陷的变厚度不锈钢板的水浸超声检测,验证了多闸门动态跟踪方法的可行性。

This study investigated the gate adjustment of ultrasonic A-scan signals in the process of ultrasonic C-scan detection system, and proposed a multi-gate dynamic tracking method suitable for workpieces with variable thickness. The basic principle was to set the detection gate on the echoes between the surface and bottom of the variable thickness workpiece, and the detection gate simultaneously tracked the surface echo and the bottom echo. This method can improve the circumstance when the surface or the bottom of the variable thickness workpiece changed during the detection process, it reduced the influence of interference waves and maximized the effective data collected by the gate. Finally, the feasibility of the multi-gate dynamic tracking method was verified by using water immersion ultrasonic testing to detect variable thickness stainless steel plates with artificial defects.